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Great News for the Great Barrier Reef: Tully River Water Quality

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Abstract

A prerequisite for meaningful environmental legislation is that it be based upon an adequate scientific understanding of the natural system to which it is applied. In 2003, the Australian Commonwealth and Queensland State governments introduced a Reef Water Quality Protection Plan, which aimed to "improve" water quality in river catchments adjacent to the Great Barrier Reef (GBR) and in nearby coastal waters. The Plan was introduced in the absence of any substantive evidence for regional degradation of GBR water quality. This paper reviews the available data regarding nutrient contents in the Tully River, north Queensland, which is cited as the best (available) evidence for human-related changes in nutrient export from (GBR) catchments(1). It is shown that the claim of human-related nutrient enrichment in the Tully River, and regionally, is without substance. No detectable trends in GBR water quality have occurred since systematic measurements were first started in the 1980s. Environmental policies that are based on mischievous claims of chimerical damage to the Great Barrier Reef damage the reputation of science as a tool for disinterested analysis, and provoke widespread cynicism in the community regarding the integrity of contemporary environmental politics.

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... The impacts of these particles and solutes can prove difficult to demonstrate as a systematic and quantitative effect on the reef environment of the GBR, which in some cases has fuelled debate in the literature (e.g. Macdonald et al. 2005;Carter 2006). Nevertheless, the GBR and its lagoon certainly receives many times the quantity of sediment and nutrients than it did before European settlement (e.g. ...
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Pollution of coastal regions of the Great Barrier Reef World Heritage Area (GBRWHA) is dominated by river discharge associated with agricultural development of the adjacent catchments. Runoff of sediment, nutrients and pesticides has sharply increased since European settlement. Since 1991 plumes from river discharge entering the GBRWHA have been mapped by aerial mapping of plume edges and concentrations of contaminants in plumes measured. Plume dispersion is governed primarily by wind speed and direction. Most plumes spread in a band up to 50 km from the coast. Particulate material discharged in the plumes is trapped within 10 km of the coast. Dissolved nutrients disperse much further and elevated nutrient concentrations are measurable at distances of hundreds of kilometres from river mouths. This differential transport of particulate versus dissolved nutrients is important for the potential effects of these materials and management of their generation on the Great Barrier Reef catchment.
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